This project uses electron microscopy, histochemistry, and autoradiography to study the biosynthesis of cartilage proteoglycans and their relationship to collagen in cartilage matrix. Current studies include (1) electron microscopy of cartilage from mutant mice; (2) autoradiography of 35SO4 incorporation into bone proteoglycans; (3) electron microscope autoradiography of 35SO4 and 3H-glucosamine incorporation into cultured rat chondrosarcoma cells; and (4) measurements of purified proteoglycan molecules from rat chondrosarcoma.